Tecumseh sparkplugs for ohv

[38racing]

I'm servicing my friend's older snowblower with ohsk120 Tecumseh ohv. When I first googled for a plug it came up equivalent to ngk b6hs . I had another matching aftermarket and was surprised that it did not have the long threaded section like most ohv including my Tecumseh vtwin which uses champion r4nc with the long threads . Finally I found in a manual that the ohsk changed plugs after a certain spec number from b6hs to rn4c. My friend's is the earlier so takes plug with less threads. Interesting is that it had a j8c in it. The correct b6hs still has about 1/8 inch more thread than the j8c.

[KE4AVB]

Some DIYers will just put in whatever fits the hole. I have short reach plugs where long reach are to be and long reach in old L head where short reach are to suppose to be. So it is not surprising when it happens here; just a lot more work at times especially when there is a hole in the piston.

[Arkie]

Some DIYers will just put in whatever fits the hole.

I have short reach plugs where long reach are to be and long reach in old L head where short reach are to suppose to be. So it is not surprising when it happens here; just a lot more work at times especially when there is a hole in the piston.

I bought a really nice little yard/garden tractor dirt cheap few years ago because they said it was always hard to start especially after it got warmed up and they were tired of trying to get it reliable.
I could see they had been into the carb, ignition system and not telling where else. B46 Onan engine.

Some DIY Bubba had installed a couple short reach spark plugs that had been in the engine forever. I had to carefully re-chase/clean the carboned up long threads in the heads so as to install the correct spark plugs. Runs and starts like new now.